This trail isn't the "world's scariest", merely the world's most poorly maintained. If it was in good shape, it may get your pulse up a little but would not cause a heart attack.
What would the Whitney main trail be like if the cables were never put in or slides were left intact? For that matter, the Half Dome trail would be suicidal for most people if the cables weren't put up or the steps on the "Quarter Dome" were left to decay.
For me, a trail is truely "scary" if it is inherently so, even under optimal conditions and top maintenance. A couple heart pounders that I've been on include the
Eagle Creek Trail in Oregon and the
ladders (unroped) up/down the cliffs to the Mer de Glace in Chamonix/Mt. Blanc.